Headrest for an ophthalmic chair or the like

ABSTRACT

A spring mounted linkage system adjustably supporting a headrest characterized by a single reciprocally movable knob uniquely capable of locking the headrest in various positons.

United States Patent 11 1 Schenk et al.

1 511 Sept. 25, 1973 A [22] Filed:

[ HEADREST FOR AN OPHTHALMIC CHAIR OR THE LIKE [75] Inventors: George F.Schenk, Williamsville;

Irwin A. Bosack, Buffalo, both of NY.

[73] Assignee: American Optical Corporation,

Southbridge, Mass.

Sept. 11, 1972 21 Appl. No.: 288,196

[52] US. Cl. 297/408, 297/410 [51] Int. Cl A474: 7/36, A470 7/42 [58]Field of Search 297/327, 408-410 [56] References Cited 2 UNITED STATESPATENTS Collura 297/408 X 3,572,835 3/1971 Kees, Jr. 297/410 FOREIGNPATENTS OR APPLICATIONS 1,334,460 7/l963 France 297/408 PrimaryExaminer-Casmir A. Nunberg Att0rney-William C. Nealon et al.

[57] ABSTRACT A spring mounted linkage system adjustably supporting aheadrest characterized by a single reciprocally movable knob uniquelycapable of locking the headrest i various positons.

4 Claims, 5 Drawing Figures lOO HEADREST FOR AN OPHTHALMIC CHAIR OR THELIKE BACKGROUND OF THE INVENTION A variety of adjustable support systemsand linkages are available for supporting headrests of the type found onvarious physicians chairs. For example, chairs of the type used by anophthalmologist, a dentist, or others rendering medical or like servicesfor a patient in a semi-reclined, yet seated position.

It is desirable that such linkage systems allow for easy positiveadjustment to a plurality of positions. The present invention provides abracket, link and arm support arrangement which is unique in the mannerin which the various'parts are locked into position. The arrangementallows for rapid and easy, yet accurate and positive positioning of theheadrest in a plurality of positions.

OBJECTS OF THE INVENTION It is a primary object of this invention toprovide a chair headrest of an improved type. It is another object ofthe invention to provide a headrest linkage system of the bracket, linkand arm type characterized by a unique position locking arrangement.

DRAWING FIG. 1 is a side elevation in partial section of a bracket, linkand arm headrest construction according to this invention.

FIG. 2 is a top elevation of a portion of the arrange ment of FIG. 1 inpartial section.

FIG. 3 is a partial section along the lineA-A of FIG. 1 indicating theinternal cooperation between parts associated with a single controlknob.

. FIG. 4 is a fragmentary section of a group of the elements associatedwith'the control knob of FIG. 3.

FIG. 5 is a fragment of the headrest locking pivot in partial section.

DESCRIPTION OF THE INVENTION In FIG. I there is shown a bracket, linkand arm headrest construction including an arm interconnected between aheadrest 11, held in a bracket 11' and an elongated link 12 by a splinedbearing 13. The opposite end of the link'12 is connected through anadditional splined bearing 14 to a chair support 15. The chair support15 is connected to the back of a chair in a conventional manner byattaching the plate 16 to the back of a chair with bolts or screwsinserted through the plurality of bolt holes 17. An exemplarychairindieating the relative position of a headrest of the type shownherein can be found, for example, in US. Pat. No. 2,672,9l7. t

The headrest 11 is attached to the arm 10 by a suitable pivot screw 20.The screw 20 is spring loaded and easily adjusted in a conventionalmanner. 'As can be seen by reference to FIG. 5, a spring loaded support21 has a central annular aperture through which extends the screw 20 tothreadilyengage the annular nut member 22. A spring washer 23 assuresfriction.

Referring again to FIG. 1, the link 12 is hollow in that a pairofsubstantially identical shafts 25 and 25' are arrangedfor reciprocalaxial movement through the respective axial passages 26 and 26' againstthe splined bearings 13 and 14. Those end portions of the shafts 25 and25 bearing against the splined bearings 13 and 14 As shown in FIG. 2,the spring 30' is fastened to the body of the link 12 by the screw .35and its other end by the screw 37 to the shaft 25. Note the screw 37 isable to reciprocally move axially of the link 12 in the groove 40.

Spring 30 is similarly fastened by the screw 38 and .screw 36 axiallymovable in the groove 41. Referring for the moment to FIG. 4, theadjacent or opposed ends of the shafts 25 and 25 are tapered and rest onopposite sides of the generally truncated conical base portion of thecam member 50. The member 50 is urged back and forth on an axis normalto theaxis on which the shafts 25 and 25 move. This motion of member 50is induced by turning the knob 51. Note the knob 51 is fastened by a setscrew 52 to the threaded shaft 53. The truncated conical portion of themember 50 terminates in a plate-like device 60. This device 60preventsthe knob 51 and associated parts from accidentally beingunscrewed sufficiently to be disengaged since the plate 60 is heldbetween the opposed tapered ends of the shafts 25 and 25' when thethreaded shaft 53 is disengaged.

I Recapitulating: a pair of splined bearings 13 and 14 whichare lockedin place with suitable set screws 70 to the arm 10 and chair support 15are free to rotate in the ends of connecting member or link 12. However,the

, connecting member or link 12 contains a knob 51 the complimentarysplines which extend axially about the outer peripheral surface of thebearings 13 and 14.

As knob 51 is threaded outwardly or retracted, the springs 30 and 30pull the shafts 25 and 25' together along the opposed surfaces of thetruncated conical cam member 50. This'allows both bearings andassociated element 10 to rotate freely to move the arrangement as shown,for example to the dotted or dashed line position 100. Rotating the knob51 in the opposite direction causes the conical base of cam member 50 toforce apart the opposed shafts 25 and 25 into locking association withthe bearings 13 and 14.

One additional element is worthy ofnote. A screw 75 (see FIG. 3)interconnects the member 50 with a threaded shaft 53 through-anoversized aperture 76. This allows the taper of the member 50 to take upvariation in the lengthsof the shafts 25 and 25.

Having thus described the invention in detail and with sufficientparticularity as to enable one skilled in the art to practice theinvention, what is desired to have protected by Letters Patent is setforth in the following claims:

What is claimed is: r

1. An adjustable headrest support linkage system of the bracket, linkand arm type comprising: head support means carried adjacent one end ofan elongated arm, the arm pivotally interconnected with an intermediate.link by a bearing, the bearing being fixed relative to the arm,thebearing pivotally associating an end portion of the arm with anintermediate link, there being a split shaft associated with the linkand arranged to move axially thereof, an additional bearing pivotallyassociated with the other end of the link and with chair supportstructure, said additional bearing being fixed relative to the chairsupport structure, locking means carried by the link intermediate itsends in position to reciprocally move the split portions axially of thelink so that opposed ends thereof are substantially coincidentally movedinto association with the bearings, there being means on said opposedends of the split shaft arranged for locking the bearings in positionupon appropriate adjustment of the locking means.

2. The arrangement of claim 1 in which said bearings are splined and inwhich the opposed ends of the split shaft have serrations arranged tomate with the splines on the bearings to lock the head support means inposi tion.

3. The arrangement of claim 1 further including spring means operativelyinterconnected between the link and the portions of the split shaftarranged to urge the split shaft elements out of locking associationwith the bearings upon appropriate movement of the locking means.

4. The arrangement of claim 1 in which said locking means is comprisedof an externally accessible knob having depending therefroma threadedshaft arranged to mate with complementary threads in the link wherebythe knob is moved into and out of engagement with said link, there beingadditional means depending axially from the threaded shaft, saidadditional means including cam surfaces arranged to cooperate withopposed ends of the split portions of the shaft whereby, upon threadingand unthreading of the knob, the cam surfaces move the shaft portioninto and out of locking association with the bearings.

1. An adjustable headrest support linkage system of the bracket, linkand arm type comprising: head support means carried adjacent one end ofan elongated arm, the arm pivotally interconnected with an intermediatelink by a bearing, the bearing being fixed relative to the arm, thebearing pivotally associating an end portion of the arm with anintermediate link, there being a split shaft associated with the linkand arranged to move axially thereof, an additional bearing pivotallyassociated with the other end of the link and with chair supportstructure, said additional bearing being fixed relative to the chairsupport structure, locking means carried by the link intermediate itsends in position to reciprocally move the split portions axially of thelink so that opposed ends thereof are substantially coincidentally movedinto association with the bearings, there being means on said opposedends of the split shaft arranged for locking the bearings in positionupon appropriate adjustment of the locking means.
 2. The arrangement ofclaim 1 in which said bearings are splined and in which the opposed endsof the split shaft have serrations arranged to mate with the splines onthe bearings to lock the head support means in position.
 3. Thearrangement of claim 1 further including spring means operativelyinterconnected between the link and the portions of the split shaftarranged to urge the split shaft elements out of locking associationwith the bearings upon appropriate movement of the locking means.
 4. Thearrangement of claim 1 in which said locking means is comprised of anexternally accessible knob having depending therefrom a threaded shaftarranged to mate with complementary threads in the link whereby the knobis moved into and out of engagement with said link, there beingadditional means depending axially from the threaded shaft, saidadditional means including cam surfaces arranged to cooperate withopposed ends of the split portions of the shaft whereby, upon threadingand unthreading of the knob, the cam surfaces move the shaft portioninto and out of locking association with the bearings.